Housing for electromagnetic interference shielding

ABSTRACT

A composition containing a polymeric matrix and a conductive filler component is provided. The conductive filler component comprises conductive particles and a polymer selected from the group consisting of substituted and unsubstituted polyanilines, substituted and unsubstituted polyparaphenylenevinylenes, substituted and unsubstituted polythiophenes, substituted and unsubstituted polyazines, substituted and unsubstituted polyparaphenylenes, substituted and unsubstituted polyfuranes, substituted and unsubstituted polypyrroles, substituted and unsubstituted polyselenophene, substituted and unsubstituted poly-p-phenylene sulfides and substiututed and unsubstituted polyacetylenes, and mixtures thereof, and copolymers thereof. Compositions of the present invention are useful as corrosion protecting layers for metal substrates, for electrostatic discharge protection, electromagnetic interference shielding, and as adhesives for interconnect technology as alternatives to solder interconnections. In addition, films of polyanilines are useful as corrosion protecting layers with or without the conductive metal particles.

This application is a divisional of U.S. patent application Ser. No.08/356,026, filed Dec. 14, 1994 now U.S. Pat. No. 5,700,398.

TECHNICAL FIELD

The present invention is concerned with polymeric compositions that areelectrically conductive. In particular, the compositions of the presentinvention contain a polymeric matrix and a conductive filler componentthat includes conductive particles, such as metal particles and certainpolymers.

The particular polymers employed, pursuant to the present invention, arethe polyanilines, polyparaphenylenevinylenes, polythiophenes,polyfuranes, polypyrroles, polyselenophene, polyparaphenylenes,polyazines, poly-p-phenylene sulfides and polyacetylenes and mixturesthereof and copolymers made from the monomers to form the abovepolymers. Any of the above polymers can be substituted or unsubstituted.

Compositions of the present invention are especially useful as corrosionprotecting layers for metal substrates, for electrostatic dischargeprotection, electromagnetic interference shielding, and as adhesives forinterconnect technology to replace solder interconnections.

According to another aspect of the present invention, substituted andunsubstituted polyanilines are used as corrosion controlling layers formetal substrates.

BACKGROUND OF INVENTION

It has been suggested to convert normally insulating thermoset andthermoplastic polymers or prepolymers into electrically conductingcompositions by admixing therewith various electrically conductive metalparticles, such as silver and copper. The possible applications for suchconducting compositions are quite extensive. For instance, it would bedesirable to use these conducting compositions for electrostaticdischarge protection, electromagnetic interference shielding, asadhesives for interconnect technology as replacements for solder jointconnections.

However, there are problems associated with this technology. Often, highlevels of the metal particles are needed to achieve the desired level ofelectrical conductivity, especially in high current carryingapplications, such as interconnect technology, where the higher levelsof electrical conductivity must be achieved. A loading level of 50% andhigher is often required for such applications. A second serious problemwith these metal fillers is that the more useful ones, silver andcopper, tend to corrode in a variety of ambients. The metal has atendency to oxidize, and thus, an oxidized layer of copper or silverwill be on the surface of the particles, and will result in loss ofconductivity, or at least a decrease in the conductivity.

Although both copper and silver are called "noble," they readily corrodein a variety of ambients. In oxygen saturated deionized water, copperand silver dissolve at a rate of about 0.2 μm/day, with no evidence ofpassivation. Both metals are susceptible to the presence of pollutants,notably chlorides and sulphur.

In the presence of humidity, pollutants and an applied electrical field(not an uncommon situation for the electronic parts in operation),copper and silver dissolve from the more positive metallic part andplate at the more negative part as dendrites. The formation of dendritescan result in electrical shorts that can lead to the failure of theelectronic device.

Furthermore, with increasing line density and decreasing dimensions, ionaccumulation alone, without dendrites, can ruin the designed electricalperformance of the product. Use of inhibitors, such as benzotriazole(BTA), greatly improves the corrosion resistance of copper and silver.However, BTA is not very protective against dissolution at potentialsabove the open circuit potential, as it may occur in a galvanic contactwith gold or platinum, or in service, with the applied field.

Moreover, to circumvent these problems, copper and silver metalparticles are often coated with other more stable metals, such as goldor nickel. This is done by electroless or electroplating processes,which add additional processing costs and pose potential environmentalconcerns, due to the chemical make-up of the electroplating baths.

SUMMARY OF INVENTION

The present invention is concerned with a composition that comprises athermoset or thermoplastic polymeric matrix, arid a conductive fillercomponent. The conductive filler component contains conductive particlesand certain polymers. The polymer is selected from the group consistingof polyparaphenylenevinylenes, polyanilines, polyazines, polythiophenes,poly-p-phenylene sulfides, polyfuranes, polypyrroles, polyselenophene,polyparaphenylenes, polyacetylenes and mixtures thereof, and copolymersthereof. These polymers can be substituted or unsubstituted. In additionthe conductivity of these polymers can be tuned from about 10⁻¹⁰ ohm⁻¹cm⁻¹ to about 10⁶ ohm⁻¹ cm⁻¹ by chemical manipulation such as byincorporation of substituents, doping levels and/or processingconditions. These polymers are also referred to hereinafter as"conducting" or "conductive" polymers.

In addition, the present invention is concerned with the use of theabove disclosed compositions, as corrosion protecting layers for metalsubstrates, for electrostatic discharge protection, electromagneticinterference shielding and as adhesives for interconnections asalternatives to solder interconnections. The present invention providesfor a simple, relatively inexpensive and environmentally safe method ofprotecting the metal particles from corrosion, without loss inelectrical conductivity. Moreover, the present invention makes itpossible to reduce the loading level required for the metal particles.

It has also been found, pursuant to the present invention, thatpolyanilines and especially alkoxy substituted polyanilines, as such,can be used as corrosion protecting layers for metal substrates.

SUMMARY OF DRAWING

FIG. 1 provides potentiodynamic polarization curves for copper coatedwith different materials.

BEST AND VARIOUS MODES FOR CARRYING OUT INVENTION

The filler component of the compositions of the present inventioncontain electrically conductive particles, and a certain amount of aconducting polymer. The particles are preferably carbon and metal, suchas silver or copper, and in the form of powder, flakes or fibers.

The polymer portion of the filler component is selected from substitutedand unsubstituted polyparaphenylenevinylenes, substituted andunsubstituted polyazines substituted and unsubstituted polyanilines,substituted and unsubstituted polythiophenes, substituted andunsubstituted polyfuranes, substituted and unsubstitutedpolyparaphenylenes, substituted and unsubstituted poly-p-phenylenesulfides, substituted and unsubstituted polypyrroles, substituted andunsubstituted polyselenophene, substituted and unsubstitutedpolyacetylenes, and combinations thereof and copolymers made from themonomers to form the above polymers. Examples of suitable substitutionsinclude alkyl aryl, alkoxy aryloxy groups, alkanyl and aralkyl.Typically, such groups contain 1-12 carbon atoms. The substitutedpolymers are preferred because they exhibit enhanced solubility andprocessability.

One type of polymer useful to practice the present invention is theconductive form of a substituted or unsubstituted polyaniline having thefollowing general formula: ##STR1## wherein each R can be H or anyorganic or inorganic radical; each R can be of the same or different;wherein each R¹ can be H or any organic or inorganic radical, each R¹can be the same or different; X is ≧1 and preferably X ≧2 and y has avalue from 0 to 1. Examples of organic radicals are alkyl or arylradicals. Examples of inorganic radicals are Si and Ge. This list isexemplary only and not limiting. The most preferred embodiment isemeraldine base form of the polyaniline, wherein y has a value of 0.5.In the above equation, the polyaniline is in the non-doped form having aconductivity of about 10⁻¹ ohm⁻¹ cm⁻¹. The polyaniline can be convertedto the conducting form by doping, which involves reacting thepolyaniline with a cationic species QA. QA can be, for example, a proticacid, wherein Q is hydrogen. The nitrogen atoms of the imine part of thepolymer become substituted with the Q cation to form an emeraldine salt,as shown in the following equation: ##STR2##

The emeraldine salt is the highly conducting form. The conductivity ofthe polyaniline can range from 10⁻¹⁰ ohm⁻¹ cm⁻¹ (characteristic of thebase and non-doped form) to about 10³ ohm⁻¹ cm⁻¹ upon full doping.

The ring substituted polyaniline, and in particular, the ortho-ethoxyderivatives, and ortho propyl derivatives exhibit appreciably greatersolubility than the unsubstituted ones.

The unsubstituted emeraldine base form of polyaniline is soluble invarious organic solvents, and in various aqueous acid solutions.Examples of organic solvents are dimethyl-sulfoxide (DMSO),dimthylformamide (DMF) and N-methylpyrrolidinone (NMP). This list isexemplary only and not limiting. Examples of aqueous acid solutions is80% acetic acid, and 60-88% formic acid. This list is exemplary only andnot limiting. The ring substituted derivatives are also soluble in moresolvents, including less polar solvents such as chloroform,methylenechloride, xylene and toluene.

Preferred polyaniline compounds in the present invention are ethoxyderivatives, represented by the following: ##STR3##

The ethoxy substituted polyaniline in the non-doped form (base) can bereadily dissolved to a 10% by weight solution in NMP, and spun atvarious rpms to form films of different thicknesses (184,339 and 477 nm,respectively). Films from this polymer are very homogenous and welladherent. Even the thinnest film behaves as a perfect barrier to oxygen,as electrochemical data show no current normally attributable to oxygenreduction. The measured cathodic current of about 2×10⁻⁷ A/cm² isindependent of film thickness, type of metal (copper, silver andplatinum) and ambient atmosphere (air and nitrogen). The current isdiffusion limited and most likely caused by reduction of ethoxy radicalor the ethoxy polymer backbone. The anodic current, metal dissolution,is in all cases greatly reduced by a factor which increases with filmthickness. The protection is substantial, in particular at highpotentials, where Cu dissolution (and similarly silver dissolution) isabout 4 orders of magnitude lower than measured on unprotected metals.

In addition, ethoxy substituted polyaniline spin-doped with acid HA,such as hydrochloric acid, can be prepared by first spin-coating of thepolymer in the non-conducting form, and subsequently doping such as bydipping the film into a 1 N aqueous hydrochloric acid solution for about1 hour and then drying. The polymer upon full doping has a conductivityon the order of 10⁻² ohm⁻¹ cm⁻¹. Its corrosion protection is similar tothat offered by non-doped ethoxy-polyaniline, except for the measurementof the oxygen reduction rate. Apparently, as the polymer is conducting,it allows a passage of electrons needed for oxygen reduction. Theprotection of the film is excellent, especially at anodic potentials.

Examples of another substituted polyaniline is ortho-propyl polyaniline.

The polyanilines, and preferably the alkoxy substituted polyanilines,such as ethoxy substituted polyanilines, as such, both in the non-dopedless conducting form and the doped more conducting form, are useful ascorrosion protecting layer on a metal substrate. The polyanilines arepreferably employed in their conducting doped form.

Examples of suitable polythiophenes are represented by the followingformula: ##STR4## wherein each R² is H or any organic or inorganicradical; wherein t≧1 and preferably wherein at least one R² is not H.

Polyparaphenylenevinylenes useful to practice the present invention havegeneral formula wherein each R³ is H or any organic or inorganicradical, and wherein s≧1. Each R³ can be the same or different: ##STR5##

Polyazines useful to practice the present invention have general formulawherein R¹⁰ is H or an organic or inorganic radical: ##STR6##

Polyfurans useful to practice the present invention have generalformula, wherein Z≧1 and each R⁴ is H or any organic radical, and eachR⁴ can be the same or different: ##STR7##

Polypyrroles which are useful to practice the present invention havegeneral formula, wherein w≧1, each R⁵ is H or any organic or inorganicradicals; wherein each one R⁵ can be the same or different: ##STR8##

Polyselenophene useful to practice the present invention have generalformula, wherein v≧1, and each R⁶ is H or any organic or inorganicradical and wherein each R⁶ can be the same or different: ##STR9##

Examples of combinations of polythiophenes, polyfurans, polypyrroles andpolyselenophene useful to practice the present invention are representedby the following equations wherein R⁴, R⁵ and R⁶ are as defined abovewherein at least two of a, b, c and d are greater than or equal to 1;m≧1; Q¹, Q² Q³ can be a vinylene group or a direct bond between adjacentconstituents: ##STR10##

Poly-p-phenylene sulfides useful to practice the present invention arerepresented by the following general formula wherein each R⁷ is H or anyorganic or inorganic radical and f≧1, each R⁷ can be the same ordifferent: ##STR11##

The article entitled New Routes to Processed Polyacetylenes, T. Swager,et al. Polymer Preprints, Vol. 30, No. 1, p. 161, April 1989, describesmethods of preparing polyacetylene from a soluble precursor, theteaching of which is incorporated herein by reference.

The conductive particles can be precoated with the above conductingpolymers prior to admixture with the polymeric matrix. In thealternative, the above conducting polymer and conductive particles canbe separately admixed with the polymeric matrix. The blending can becarried out by dispersion or more preferably, by solution blending. Whenthe above defined conducting polymer and conductive particles areadmixed with the polymeric matrix, lower amounts of conductive particlesare needed to obtain a given conductivity.

When used to precoat the conductive particles, the conducting polymer isgenerally used to provide coatings about 0.1 to about 5 microns thick,and preferably about 0.15 to about 2-5 microns thick.

The particles can be solution coated.

The polymeric matrix employed, pursuant to the present invention, can bethermoset or thermoplastic polymeric materials. The preferred polymersare the polyepoxides, polyacrylates, polymethacrylates, polysiloxanes,and polyimides, such as the polyimide siloxanes, polyurethanes,polyolefins, and polyamides. Mixtures of polymers as well as copolymerscan be employed when desired.

The composition of the matrix polymer, the conducting polymer and theconducting particles is as follows: The conducting polymer is typicallyemployed in amounts of 0.3 to about 90, and preferably about 0.5 toabout 50% by weight, and most preferably about 1 to about 10% by weightbased upon the total weight of the polymeric matrix.

The amount of conducting particles is typically about 40% to about 95%by weight, preferably about 75 to about 95% by weight, and mostpreferably about 80 to about 90% by weight relative to the total polymercontent (conducting polymer and matrix polymer).

The compositions of the present invention when used as a corrosionprevention layer are typically employed at thicknesses of about 500 Å toabout 5 μm, and preferably about 1000 Å to about 5000 Å. The substratesemployed are typically copper and silver.

The compositions of the present invention can be used to bond together asemiconductor with a substrate as a replacement for solderinterconnections.

The compositions of the present invention are useful as electromagneticinterference (EMI) coatings on a dielectric surface. For example,electrical components are frequently contained within dielectrichousings, such as cabinets, molded plastics and the like. To reduce thesusceptibility of the electronic components contained within the housingto electromagnetic radiation, the dielectric housing can be coated withthe compositions of the present invention.

The following non-limiting examples are presented to further illustratethe present invention:

EXAMPLE 1 Preparation of Polyanilines

Polyaniline (unsubstituted) was prepared by the chemical oxidativepolymerization of aniline in aqueous/1 normal hydrochloric acid usingammonium persulfate as the oxidant. The conducting polyanilinehydrochloride salt is isolated from the reaction mass. The HCl salt isconverted to the polyaniline base form (non-conducting) by reacting with0.1M NH₄ OH. The isolated polyaniline base can then be doped with thedesirable acid or alkylating agent to give a conducting derivative.

The substituted polyaniline derivatives were prepared by the oxidativepolymerization of the appropriate ring-substituted aniline manomer alongthe lines of the method described. For example, the ethoxy-substitutedpolyaniline was prepared by the oxidative polymerization ofo-phenetidine. The ethoxy-polyaniline hydrochloride salt and base formwere isolated as described above.

The conducting ethoxy polyaniline doped with toluene sulphonic acid wasprepared by reacting the ethoxy polyaniline base powder heterogeneouslywith 1 normal aqueous toluenesulfonic acid. It can also be prepared byreacting a solution of ethoxy-polyaniline base in NMP orgamma-butyrolactone with toluenesulfonic acid.

Alternatively, o-phenetidine can be polymerized in the presence ofaqueous 1 normal toluene sulfonic acid instead of hydrochloric acid toyield the conducting ethoxy polyaniline tosylate.

The ethoxy-polyaniline tosylate is dissolved in NMP (N-methylpyrrolidinone) or gamma-butyrolactone to prepare 6 weight % solutions.

EXAMPLE 2 Preparation of Coated Silver Particles

An Ethoxy polyaniline tosylate solution prepared in Example 1 was addedto the silver particles. The particles were stirred in the conductingsolution. The particles were then filtered and dried under vacuum.

EXAMPLE 3 Preparation of Conductive Composition

A conductive paste is made by combining the polyaniline coated silverpowder of Example 2 with the host polymer, such aspolymethylmethacrylate in an appropriate solvent system, such as xylene.The solvent is chosen so as not to dissolve the polyaniline. Thematerials are blended by a dispersion technique or high shear mixing.

EXAMPLE 4 Blending of a Host Polymer and Polyaniline and Metal Fillers

To a host resin, in particular, polymethylmethacrylate ingamma-butrolactone was added a gamma-butrolactone solution of the ethoxypolyaniline tosylate. The two polymers mixed well. To the polymer blendsolution were added silver particles, by dispersion mixing. Theresulting mixture was used to spin-coat conducting coatings. The mixturecan also be processed by conventional means to fabricate conductingfilms or composites suitable for the uses disclosed above.

EXAMPLE 5

Corrosion was measured in two complementary ways. The first water droptest 1 uses an electrochemical technique described as follows:

Evaluation of the corrosion rate by electrochemical techniques is directand precise, but not readily applicable to conditions of atmosphericcorrosion. Tests were conducted in a miniature cell, that was designedin an attempt to bridge the benefits of electrochemical testing and thechallenges presented by corrosion reactions under a thin layer of anelectrolyte. The cell can use a droplet of water as an electrolyte, asdescribed by Brusic, et al., J. Electrochem. Soc., 136 42 (1989).

The set-up consists of the sample (working electrode) masked withplating tape to expose a 0.32 cm² area. Pt mesh (counter electrode), anda mercurous sulfate electrode (reference electrode), with a filter paperdisk separating each electrode. The procedure was as follows: Themetallic sample, with or without polyaniline coating, was placed on asmall jack, and the working area, covered with a tightly fitted filterpaper and a flat Pt mesh, was maneuvered into a center of the opening ofa vertically positioned and a rigidly held Beckmann fitting. The innerdiameter of the fitting was 8 mm, i.e, large enough to easily expose theentire working area that has a diameter of 6.4 mm. The sample was thenraised and kept in place at a hand-tight pressure against the fitting.The second filter disk was an Eppendorf pipette, and the referenceelectrode was positioned over the sample using the fitting as a holder.A typical droplet size was 20 μl. Due to small distances between theelectrodes, the ohmic resistance in the cell was relatively small evenwith electrolytes such as deionized and triple-distilled water. As theohmic resistance of the cell was only about 800 in the first seconds ofmeasurement, insignificant errors in the evaluation of corrosion ratesare introduced. The procedure was to monitor the corrosion potential forabout 15 minutes and periodically measure the polarization resistance byscanning the potential ±20 mV from the corrosion potential at 1 m V/s.The corrosion rate was calculated using the Model 352 SoftCorr IIsoftware by AG&G Princeton Applied Research. The potentiodynamicpolarization curve was then measured at a rate of 1 mV/s from 0.25 Vcathodic of the corrosion potential. The corrosion rate was evaluated byan extrapolation of the cathodic and anodic currents to the corrosionpotential.

Excellent corrosion protection has been measured with unsubstituted,undoped polyaniline base, FIG. 1 (curve 3). The film was processed froma 5% solution in NMP, and baked after spin-drying at 80° C. for 4minutes. Its conductivity is low, 10⁻¹⁰ ohm⁻¹ cm⁻¹, and thermalstability is up to >400° C. The film adheres well to the metal surfaceand acts as a barrier to all corrosion reactions. Potentiodynamiccurrent-potential curve looks similar to one obtained on unprotectedcopper, but the corrosion current is lower and the corrosion potentialhigher for copper covered with this film. This indicates that the filmalso affects exodus of copper ions, i.e., the anodic reaction.

The surprisingly effective protection is observed with ethoxysubstituted non-doped polyaniline base, FIG. 1 (curve 1). This polymeris applied from a 10% solution in NMP, and spun at various rpms to formfilms of different thicknesses (184, 339 and 477 nm, respectively). Thefilms are very homogenous and well adherent. Even the thinnest filmbehaved as a perfect barrier to oxygen, as electrochemical data show nocurrent normally attributable to oxygen reduction. The measured cathodiccurrent of about 2×10⁻⁷ A/cm² is independent of film thickness, type ofmetal (copper, silver and platinum tested) and ambient atmosphere (airand nitrogen tested). The current is diffusion Limited and most likelycaused by reduction of ethoxy radical or the ethoxy polymer backbone.The anodic current, metal dissolution, is in all cases greatly reducedby a factor which increases with film thickness. The protection issubstantial, in particular at high potentials, where Cu dissolution (andsimilarly silver dissolution) is about 4 orders of magnitude lowerthanmeasured on unprotected metals.

Ethoxy substituted polyaniline doped with hydrochloric acid was preparedby spin-drying the non-doped ethoxy base polyaniline and then doping bydipping into 1N hydrochloric acid. The doped polymer has a conductivityon the order of 10⁻² ohm⁻¹ cm⁻¹. Its corrosion protection is similar tothe one offered by the non-doped ethoxy-polyaniline base, except for themeasurement of the oxygen reduction rate. Since the doped polymer ismore highly conducting, it allows a passage of electrons needed foroxygen reduction. The protection of the film is excellent, especially atanodic potentials.

The second method:

Water Drop Test II:

A drop of water is placed across adjacent metal leads. A potential of 5Vis then applied across the metal lines and failure or time for dendriteformation is measured. The time is given from the time the voltage wasapplied until shorting between the lines is observed.

Test vehicle for measurement:

Test vehicle: Cu lines applied by evaporation on 0.5 μm SiO2 coatedwafers. Copper line patterns include: 1) line width--8 mils spacing--16mils 2) line width--6 miles spacing 12 mils.

Bare Copper (Cu)

The copper lines were cleaned with a 1.5% acetic acid solution to removenative oxides, rinsed with deionized water and dried.

Results are as follows:

3 repeated test measurements:

16 mils spacings--45 seconds, 48 secs, 51 secs for dendrites to form

12 mils spacings--39 seconds, 42 secs, 40 secs for dendrite to form

Copper Lines Treated with Benzotriazole (BTA) Solution

Copper was dipped in 1.5% acetic acid, rinsed with DI water; while thecopper was still wet, it is dipped in mildly alkaline KOH solution(pH≈10) for 10 minutes. This results in formation of Cu₂ O (about 2 nmthick). This is followed by a water rinse. The sample is then dippedinto a BTA solution for 10 minutes (1 g BTA/1 liter H₂ O), rinsed anddried.

For both copper and silver lines (same width and spacings) immediatedendrite formation occurred with the water drop test for both baresurfaces and BTA coated surfaces.

Ethoxy polyaniline (base or non-conducting form)

A 10% weight solution in NMP of the ethoxy polyaniline base was used tospin-coat films on wafers with copper and silver lines (as describedabove). Spinning at 3000 rpm/30s and softbaking 85° C. for 5 minutesresulted in a 5159 Å thick film.

Water Drop Test After 220° C./30 Minutes Storage

Copper and silver lines with the 5159 Å ethoxy-polyaniline film did notform any dendrite, even after 30 minutes (water drop test).

Temperature and Humidity Test (85° C. 80% relative humidity)

The 5159 Å thick film of the ethoxy non-doped polyaniline base coatedsilver and copper surfaces were tested under the above temperature andhumidity conditions. Test results for both silver and copper show thatafter 1076 hours storage at the above T:H conditions, no dendritesformed even after 30 minutes in the Water Drop II Test. This is both forthe 12 mils and 16 mils lines.

Temperature/Humidity/Bias Voltage Test

Leakage current is continually monitored and failure is flagged when theisolation resistance reading between the 2 lines is less than 16mega-ohms. Test is done while wafer is in the oven at 85° C. and 80%relative humidity. The copper and silver line pattern used were a) 8mils wide 16 mils spacings and b) 6 mils wide 12 mils spacings. Theapplied voltage was 3 volts and 14.99 volts. The polyaniline coatedwafers passed 500 hours and 1000 hours.

Ethoxy Polyaniline Doped With Hydrochloric Acid (more highly conductingForm of Polymer

a. thickness of the coating was 5000 Å. Room temperature water drop testresults: No dendrite formation even after 30 minutes (similarly to thebase form) Example 5.

b. Temperature/humidity storage (85° C. for 1016 hours) Water drop testresults showed no dendrite formation even after 30 minutes test.

What is claimed is:
 1. A housing for electromagnetic interferenceshielding comprising a composition comprising a thermoset orthermoplastic polymeric matrix, and a conductive filler component, wheresaid filler component comprises electrically conductive particles and atleast one conducting polymer selected from the group consisting ofsubstituted and unsubstituted polyparaphenylenevinylenes, substitutedand unsubstituted polyanilines, substituted and unsubstitutedpolyazines, substituted and unsubstituted polythiophenes, substitutedand unsubstituted polyparaphenylenes, substituted and unsubstitutedpoly-p-phenylene sulfides, substituted and unsubstituted polyfuranes,substituted and unsubstituted polypyrroles, substituted andunsubstituted polyselenophenes, substituted and unsubstitutedpolyacetylenes, mixtures thereof, and copolymers thereof, coated onto adielectric housing.
 2. The housing of claim 1 wherein the amount of saidconducting polymer is about 0.3 to about 90% by weight of the total ofsaid polymeric matrix.
 3. The housing of claim 2 wherein the amount ofconductive particles is about 40 to about 95% by weight based upon thetotal of said conducting polymer and said polymeric matrix.
 4. Thehousing of claim 1 wherein said polymeric matrix comprises at least onepolymer selected from the group consisting of polyepoxides,polyacrylates, polysiloxanes and polyimides, polymethacrylates,polyurethanes, polyolefins, and polyamides.
 5. The housing of claim 1wherein said particles are metal.
 6. The housing of claim 1 wherein saidparticles are silver or copper.
 7. The housing of claim 1 wherein saidparticles are carbon.
 8. The housing of claim 1 wherein said particlesare precoated with said conducting polymer.
 9. The housing of claim 1wherein said polymer is a polyaniline.
 10. The housing of claim 9wherein said polyaniline is an alkoxy substituted polyaniline.
 11. Thehousing of claim 1 wherein said composition is in the form of a paste.12. The housing of claim 1 wherein said conducting polymer hasconductivity of about 10⁻¹⁰ ohm⁻¹ cm⁻¹ to about 10⁶ ohm⁻¹ cm⁻¹.
 13. Thehousing of claim 1 wherein said conducting polymer is unsubstituted. 14.The housing of claim 1 wherein said conducting polymer is substitutedwith at least one member selected from the group consisting of alkyl,aryl, alkoxy, aryloxy, alkaryl, aralkyl, Si and Ge.
 15. The housing ofclaim 14 wherein said member is at least one member selected from thegroup consisting of alkyl, aryl, alkoxy aryloxy, alkaryl and aralkyl andcontains 1-12 carbon atoms.
 16. The housing of claim 1 wherein theamount of conductive particles is about 75 to about 95% by weight basedupon the total of the conducting polymer and the polymeric matrix. 17.The housing of claim 1 wherein the amount of conducting particles isabout 80 to about 90% by weight based upon the total of the conductingpolymer and the polymeric matrix.
 18. The housing of claim 16 whereinthe amount of the conducting polymer is about 0.5 to about 50% by weightof the total of the polymeric matrix.
 19. The housing of claim 16wherein the amount of the conducting polymer is about 1 to about 10% byweight based upon the total weight of the polymeric matrix.
 20. Thehousing of claim 1 wherein the composition is obtained by separatelyadmixing the conducting polymer and the conductive particles with thepolymeric matrix.